vadergator

first off, I KNOW that i'm on the wrong thread. desperation causes one to reach out to every avenue. i'll make this short and if someone replies, i'll give more info if needed. here is the million dollar question : what would cause a jeep; that runs and sounds great with no problems at all ; to not start after sitting for an hour after any length of time driven? less than an hour sitting, fires right up. 97 Jeep Grand Cherokee Laredo 4.0L inline 6 2WD. 3 garages and 15 mechanics later, i'm still walking instead of driving. help me obi-wan , you're my only hope.

DirtRoadXJ

how do you start it after its been sitting for more than an hr? obviously youve had it started.

Lead Foot

Exactly. You stated your question like this has happened more then just once or twice. So how do you eventually get it started each time?

mdnov

Can you give any more info?

OEJ

we need to know what parts have allready been thrown at it. I mean damn..15 mechanics???? def need more info overall. dont worry about length over description.
gives the long version and we will do our best.

TN12valve

CSPS?

vadergator

:fu rious: here's some more info. the jeep starts up and runs fine. drive all over town with multiple stops for various lengths of time. if less than an hour, fires right up. if over an hour, turns over but, doesn't fire up. in the past few months, it would ( after sitting over an hour ) crank up and die after running a few minutes during warm-up period. have to wait about 5 - 10 minutes before it would start again. if you tried before that length of time it would either just turn over or fire up and sputter a prolonged stalling effect. sometimes there would be a strong exhaust smell. if i hit the gas pedal to baby the motor, after stalling it would have a strong gas odor in the exhaust smell. 99% of the time that's not the case. only if i press the gas pedal. my IAC went bad causing my gas to run too lean and foul out my upstream O2 sensor & spark plugs. had a horrible idle because of this. replaced the IAC, O2 sensors, and plugs. when i first got the jeep, ran great for about 3 weeks. had all kinds of stalling and starting issues. changed my white powder coated coil, cap & rotor, plug wires & plugs, cam position sensor, crankshaft position sensor, O2 sensors, and battery ( over 7 years old ). wouldn't due nothing when i turned on the key. backed out the pcm screws a 1/4 inch, fired right up and ran great for about 2 months. started having the stalling issues when i drove around. suddenly without warning. instant shut off. on occasion, the prolonged sputtering, shaking, belching shut off with foul odor smell. replaced the catalytic converter & muffler ( discovered about 30 nail holes tapped in the cat & muffler. ran great until it would sit for an hour. just to be sure of no defective parts from auto store, replaced coil; and cps sensor. i usually could get my vehicle home every nite after the battle for 30 - 45 minutes of starting and stalling during warm up. noticed rpms getting low on odometer during idle warm up with a misfire also. this led to the fouled O2 sensor & plugs, due to the lean fuel mixture. replaced the IAC and O2 sensor and plugs. starts up evey day just beautiful. warms up just fine. drive it around with no problem. after sitting for over an hour, turns over without firing up. twice i had to tow the jeep home due to 100% loss of fuel pressure & spark at the same time while it sat for the hour. just lost it. next morning, it's all back to normal on it's own and fires right up and i drive all over town again. stop for 10, 20, 30, 40, 50 minutes with motor off. cranks right up and off i go. sit for 1 hour or longer, turns over but, doesn't fire up. it isn't going anywhere. try it twice, just turns over. 3rd or 4th try, it fires up and stalls in about 5 seconds or less. runs beautiful for those few seconds i might add. just instant shut off. not prolonged in any way. it's been in three different shops and nobody can figure out what the problem is. i have told them every last detail. even on about 5 occasions when i made a turn and pressed the gas to accelerate, how the motor / tranny seemed to not respond for about 5 seconds and then ran great again. i thought it might be the ignition control module but, my 97 doesn't have one. as of today, i have changed the following parts on my own just trying to see if something would correct this problem from hell. here's my list : ASD RELAY , O2 SENSORS , CPS TWICE , CAMSHAFT POSITION SENSOR , TPS SENSOR, IDLE AIR CONTROL VALVE SENSOR , COOLANT TEMP. SENSOR , INTAKE AIR TEMP. SENSOR , COIL TWICE , PLUGS , PLUG WIRES , CAP & ROTOR , VALVE COVER & THROTTLE BODY GASKETS ( JUST WAS TIME FOR IT ) HAD FUEL PRESSURE & DELIVERY CHECKED OUT ( PERFECT WORKING ORDER WITH A PRESSURE RATING OF 49 , HAS TO BE BETWEEN 44 & 54 ON MY JEEP ) , HAD THE ELECTRICAL SYSTEM CHECKED OUT ( PERFECT WORKING ORDER ) , I TOOK OFF & CLEANED MY THROTTLE BODY THOROUGHLY WITH A TOOTHBRUSH , TOOK CONTACT/ ELECTRICAL CLEANER SPRAY TO EVERYTHING WITH AN ORIFICE , ADDED #4 GROUND WIRE FROM BATTERY TO RADIATOR SUPPORT BRACKET & FROM FUEL RAIL BOLT TO FIREWALL ( THERE WAS NO GROUND FROM THE BLOCK TO THE FIREWALL ) TO STOP MY BATTERY GAUGE AND TEMP GAUGE FROM FLUTTERING AT TIMES , AND MY BATTERY. THE JEEP RUNS LIKE SHOWROOM FLOOR QUALITY UNTIL IT HAS SAT FOR AN HOUR AFTER BEING DRIVEN. I AM HOPING THAT SOME POOR SOB OUT THERE HAS ENCOUNTERED HIS OWN JEEP FROM HELL WITH SIMILAR EXPERIENCES. any suggestions would help. the current 7 mechanics are focusing in on the exterior ignition switch box. they have been going sleepless for about a week. the prior 15 - 20 mechanics are now in AA and under going deep, psychological therapy while pondering retirement. i'm just waiting for the jeep to start driving itself around like the movie Christine. i'm considering a priest for an exorcism. have come close to going to jail due to Jeep-induced road rage. jesus isn't helping so i'm asking you. any help would be appreciated.

DirtRoadXJ

have you driven it waited an hr and then spark tested each plug?

OEJ

ok. i had something similar to ur nightmare goin on. after i went through every ground strap and connector with electric cleaner and dialectric grease; i ended finding out the the pins on my cpu hadsome whit build up. so i disconnect the battery,sprayed contact cleaner on the cpu pins and VERY VERY GENTLY hit with a wire brush.

took the cpu connectors and sprayed them and let them dry. i physically smeared diaelctric grease on the cpu pins. plugged them in and connected the battery;....and boom, she started right up and has been fine for over a year now.

mine was doing what urs is doing just only about 1 time a month.
if this DOESN'T work i would replce the cpu.
let me know how you make out.

holycaveman

I did not see a fuel pump listed on there? And I don't care if you had your fuel pressure tested while its running.

If you have a bad pump you possibly could be losing your prime, and or the fuel pump contacts not working properly.

holycaveman

Before you buy any more parts. Next time it doesn't start. Take a small amount of fuel and poor down the intake. You should get some sign of life. If you don't. You have a spark issue. If you do get some life, you have a fuel issue.

Simple way to diagnose your problem. I ended up have a bad cam sensor. When I poured fuel down the intake(small amount) it fired up. Cam sensor was not letting the injectors open.

Anyways, this should help.

01xjMontucky

off topic, but sweet avatar, caveman

Hope you get it sorted out. I have a short fuse and I'd probably have broken something on my cherokee by now out of frustration.

OEJ

[QUOTE=holycaveman;2183221]Before you buy any more parts. Next time it doesn't start. Take a small amount of fuel and poor down the intake. You should get some sign of life. If you don't. You have a spark issue. If you do get some life, you have a fuel issue.

Simple way to diagnose your problem. I ended up have a bad cam sensor. When I poured fuel down the intake(small amount) it fired up. Cam sensor was not letting the injectors open.

cam sensor was replaced. caveman,but he could have gotten a bad one. cs and cps must be tested again.

i would check these things first. they must be eliminated.
then once they check out, check the injectors and then follow my cpu rightup.

holycaveman

[quote=OEJ;2183787]Yes that was just an example of how mine was diagnosed. He needs to confirm the spark condition at time of trouble. Then move on from there. The gas through the intake trick is a simple way to check.

Like you said, it could be the cpu, or the fuel pump.

holycaveman

Thanks. I am just glad the wall did not cave......in